The basic idea of using a hollow-core waveguide as an absorption cell in a spectroscopic gas measurement system is proposed. Measurements of NH3 gas concentration were made with different absorption methods at an absorption wavelength of 10.719 μm and a nonabsorption wavelength of 10.697 μm and by using a 1-m hollow-core waveguide whose transmission loss was approximately 1 dB/m in a CO2 laser with wavelengths ranging from 10.261 to 10.719 μm. The hollow-core part of the waveguide was filled with NH3 gas to form an absorption cell through which the two wavelengths were transmitted. The minimum detectable concentration level of the measurement system was limited to 5 parts in 106 because of the limitations of the manometers used in the gas-concentration monitor.
© 1993 Optical Society of America
Original Manuscript: July 23, 1993
Published: December 15, 1993
Yasunori Saito, Tatsunori Kanaya, Akio Nomura, and Tetsuo Kano, "Experimental trial of a hollow-core waveguide used as an absorption cell for concentration measurement of NH3 gas with a CO2 laser," Opt. Lett. 18, 2150-2152 (1993)